JPH0613995B2 - Torque detector for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION “Industrial field of application” The present invention is used for controlling, designing, or any other application of an internal combustion engine, and corrects the engine internal torque by correcting a cylinder internal pressure of the engine with a reference value. The present invention relates to an internal combustion engine torque detection device.

“Prior Art” Control of an internal combustion engine, for example, optimal control of air fuel consumption or ignition timing of each cylinder enables realization of low fuel consumption without reducing the output of the vehicle. Further, in an internal combustion engine, responsiveness (so-called response) plays an important role. The torque of the engine is useful information for performing these controls.

Conventionally, there are some methods as such a torque detection device for an internal combustion engine. As one of the methods, there is a method in which a pressure detecting element or a force meter using a strain gauge is provided in the support portion of the engine body, the reaction force due to the combustion pressure is detected, and the engine output is indirectly obtained. In this case, in order to prevent the vibration of the engine from being transmitted to the vehicle body, the engine support portion is configured to include a soft spring element, and the spring and the engine body constitute a vibration system. The natural frequency of this vibration system is usually set slightly lower than the idle speed.

Therefore, during transient motion such as load or unload, problems such as delay of response of engine torque and difficulty of transmission of torque of high frequency component occur due to deformation of soft spring or low natural frequency. Further, in the vicinity of the idle rotation speed, the torque detection unit detects the load that makes the vibration of the vibration system composed of the engine mass and the spring of the engine support unit,
There is a problem that the output of the detector includes a signal other than the engine torque. Further, in this method, since the detection element and the like are inserted into the engine and the mount joint portion thereof, there is a problem in that the detection accuracy and reliability are also affected by the tightening force of the joint portion.

In addition to this, there are some methods of directly detecting the engine output torque. That is, it is a method of measuring the information generated by the twist of the output shaft of the engine that occurs during torque transmission.A strain gauge is attached to the rotating shaft, and the strain generated by the twist of the shaft is detected as a change in the resistance of the gauge, and the slip ring and the rotary transformer are detected. Alternatively, there are a method of achieving information by a wireless telemeter and a method of measuring a twist angle corresponding to the torque of the output shaft as a phase difference of a waveform generated by an electromagnetic pickup or the like. However, since these need to take information from the rotating body, the structure is complicated and expensive, and the weight is large, and it is practically difficult to use as a torque detection device for engine control or a feedback element. In particular, it is needless to say that a torque meter using a slip ring has problems such as vibration and wear of slip ring contacts, and it is difficult to endure long-term use. As a method of directly detecting the engine torque, a change in magnetic permeability caused by the torque acting on the crankshaft is detected by a magnetic circuit. This method has the advantage that the crankshaft torque can be directly detected without contact and the structure is relatively compact.
However, in terms of engine torque detection, the torque detection position must be provided between the flywheel and the cylinder closest to the flywheel, and the shaft portion must be lengthened to detect this torque. The bending vibration of the crankshaft with the mass as the mass is easily generated, and the bending vibration causes a change in the clearance between the sensor and the crankshaft, which deteriorates the accuracy of the torque detection device. Further, the crankshaft needs to have a strength that does not damage the bending load or the torsional load. This means that a quenching and tempering material of medium carbon mechanical structural steel or a soft magnetic material such as spheroidal graphite cast iron, which is not necessarily suitable for a sensor material, is used as the material of the crankshaft, and it is difficult to put it into practical use.

There is also a method of obtaining a PV diagram by detecting the cylinder internal pressure and the crank angle, calculating the indicated horsepower from the area, and obtaining the average torque for each cylinder from this, but signal processing until obtaining the average torque is also possible. In addition to the long time and difficulty in calculation speed, this method can obtain the average torque only after the completion of one cycle, and detects the momentary torque of the engine, that is, the transient torque fluctuation. Not a thing. On the other hand, there is a method of obtaining a so-called torque curve showing a torque change with respect to a time change by detecting the cylinder internal pressure and the crank angle and considering the effect of the inertial force of the reciprocating motion part. However, this method is used for the torsional vibration analysis of the crankshaft and cannot be used as an engine torque detecting device.

The indicated horsepower measuring system for a piston type engine disclosed in Japanese Patent Laid-Open No. 53-54077 discloses a cylinder internal pressure P (t) with respect to time and a linear velocity V of the piston with respect to time.
Since the product of (v) and the cross-sectional area A of the piston is obtained, and further, in order to obtain the average output W made in one rotation, it is integrated for one rotation T and is averaged in one rotation T. It requires a long calculation time and cannot detect the horsepower of the internal combustion engine every moment.

"Problems to be Solved by the Invention" The present invention is to eliminate the drawbacks of these conventional engine torque detection devices, and it is possible to detect the momentary torque of an internal combustion engine in a short calculation time. It is an object of the present invention to provide a reliable and simple structure torque detection device for an internal combustion engine.

"Torque Measuring Principle of the Present Invention" First, the torque measuring principle of the present invention will be described. First
The drawing is a diagram for explaining the principle of obtaining the engine generated torque for one cylinder from the cylinder internal pressure Pi and the reciprocating portion inertia force Fo in an internal combustion engine. Reference numeral 1a is a cylinder of an internal combustion engine, 1b is a piston, 1c is a connecting rod, and 1d is a crank arm. When the cylinder internal pressure applied to the piston 1b is Pi and the piston area is A, Fp due to the gas pressure applied in the vertical direction to the piston 1b is expressed by the following equation (1).

Fp = PiA (1) The reciprocating mass is mrec, the radius of the crank arm 1d is r, the length of the connecting rod 1c is the crank angular velocity, and the inertial force Fi in the vertical direction is It is expressed by equation (2).

Therefore, the total sum Fo of the forces applied to the piston is expressed by the following equation (3).

In such a state, the torque T acting on the crankshaft in the rotational direction (torque generated by one cylinder) is given by the following equation (4).

The torque of the multi-cylinder internal combustion engine can be easily and momentarily obtained by adding the torque per cylinder thus obtained.

However, since the influence of the inertial force is smaller than that of the cylinder internal pressure, the present invention provides a torque detection device that can be used practically by detecting the cylinder internal pressure with sufficient accuracy.

"Means and Actions for Solving Problems" The torque detection device for an internal combustion engine according to the present invention detects the pressure fluctuation in the cylinder of the internal combustion engine E as shown in FIG. 2 and FIG. A pressure correction means 2 for correcting the cylinder pressure using a preset crank angle pressure level as a reference value, a crank angle detection means 3 for detecting the crank angle of the internal combustion engine, and a cylinder pressure of the pressure correction means 2. Calculation is performed based on the crank angular velocity from the crank angle detection means 3 and converted into a net torque generated by the engine E,
And a torque calculating means 4 for generating a signal corresponding to the net torque. Further, according to the present invention, in the torque calculating means, the drive torque detection for calculating the component corresponding to the drive torque from the engine generated torque by designating a crank angle range of about 100 ° from the top dead center to the top dead center of the explosion stroke. It is equipped with means.

According to the present invention, the engine E is provided with a pressure detector for measuring the in-cylinder pressure for supplying a signal to the pressure detecting means 1 and a sensor for supplying a signal to the crank angle detecting means 3 for measuring the crank angle. It suffices to install it, and it is not necessary to modify the output shaft to which the output torque of the engine is transmitted or a torque detector on the support part where the torque reaction force of the engine acts as in the past, and to modify the combustion of each cylinder. Corresponding fast torque of varying speed can be detected by a simple method, and the above-mentioned object of the present invention is achieved.

As described above, one of the points of interest of the present invention is to provide the pressure correction means 2 for correcting the pressure level using the preset crank angle as a reference value. This component is for correcting the zero drift of the pressure of the pressure detector and other changes in the reference value because the temperature condition of the engine changes when the engine is moved under various motion speeds and load conditions. FIG. 3 is an example of the measurement of the finger pressure of the fourth cylinder of an in-line four-cylinder engine, and shows that the cylinder pressure P has a large zero drift due to the difference in load such as explosion and exhaust. If the torque is obtained based on such a measurement result, it corresponds to the torque of the engine. Therefore, the device of the present invention is provided with the pressure correction means 2. In the pressure sensor, the change of pressure sensitivity becomes a problem with zero drift. FIG. 4 shows changes in pressure sensitivity ΔP with respect to temperature Temp. The pressure sensor used is a foil gauge.
Changes in pressure sensitivity due to temperature are tested in the range of -50 ° C to 250 ° C, and are arranged based on the test temperature of 100 ° C, and the changes are within ± 3%. The change in pressure sensitivity with time was extremely small. In order to obtain the engine torque based on the pressure in the cylinder based on the results of these studies, it is necessary to provide the pressure correction means 2 for correcting the level of the pressure in the cylinder as in the present invention described above. I reached the conclusion. FIG. 5 shows an experimental system for confirming this conclusion. The engine E has four in-line cylinders. A foil strain gauge was attached to the fifth fifth journal from the engine front of the crankshaft of this engine E, the engine output torque was measured, and this signal was taken out from the rotating body using an FM telemeter. The fifth journal torque measured by this foil strain gauge is shown as a solid line, and the engine torque calculation result (output of the torque calculation means 4 shown in FIG. 2) by the device constructed as an example of the present invention is shown as a dotted line in FIG. . FIG. 7 exemplifies a comparison in which the torque calculation result (the output of the torque calculation means 4 when the pressure correction means 2 of FIG. 2 is not included) according to the prior art not using the present invention is a dotted line and the above measurement result is a solid line. To do. FIG. 6 and FIG. 7 are the results of measurement when the engine was operated across the corner with the throttle valve fully open to fully closed. The result measured by the device according to the prior art which does not include the present invention is not compatible when the load is changed from high load to low load, but the torque measurement result by the device of the present invention shows good correspondence for both high load and low load. As shown, the effect of the present invention is clear.

FIG. 2 shows the torque calculating means 4 or 8 according to the present invention.
From the engine torque detected by the torque correction means 5 shown in the figure, the engine torque may be time-averaged in order to obtain the drive torque that is the power of the engine. But four cylinders, four
In the case of a cycle internal combustion engine, one cycle is completed by a combination of intake stroke, compression stroke, explosion stroke, and exhaust stroke of each cylinder as shown in FIG. 11, and each stroke is performed within a crank angle Ac of 180 °. Therefore, from the result of the drive torque obtained based on the output corresponding to the torque during the explosion stroke of 180 °, it is not possible temporally to control the ignition timing or the intake stroke of the next explosion stroke. is there. As a result of various studies by the inventor to solve this problem, as a driving torque from the characteristics of the pressure in the cylinder, the driving torque is in the range of about 90 ° to 100 ° from the top dead center TDC of the explosion stroke to the ATDC after top dead center. The time average value of 90% or more of the value in the range of TDC to 180 ° ATDC was found, and it became clear that the ratio did not change significantly depending on the engine operating conditions.
It was found that control can be performed between C90 ° and 100 ° or later and ATDC180 °.

Based on the results of this examination, the present inventor determines the crank angle determined from the engine torque of the torque calculation means 4 of the present invention shown in FIG. 2 or the torque correction means 5 of the present invention shown in FIG. The present invention has been devised, which is provided with a drive torque calculating means for calculating the drive torque by performing a calculation between the two.

FIG. 12 shows a device of the present invention provided with such a driving torque calculating means 6, which includes a pressure detecting means 1, a pressure correcting means 2, a crank angle detecting means 3, a driving torque calculating means 6, and the driving torque calculating means 6. A CPU device 7 for determining the injection amount of fuel into each cylinder by a signal according to the driving torque, and a fuel injector 8.

The device of the present invention detects the drive torque by the drive torque calculation means from the time TDC of the explosion stroke in the range of about 90 ° to 100 ° ATDC.

Therefore, the device according to the present invention makes it possible to rapidly control the fuel injection amount, the air-fuel ratio, the ignition timing, etc. in accordance with the engine torque.

[Other Embodiments] As shown in FIG. 6, the engine torque calculated and detected by the device of the present invention based on the cylinder internal pressure is slightly larger than the torque measured by the fifth journal. The difference is that the engine output torque measured by the 5th journal is a value obtained by subtracting the friction torque, the accessory drive torque, etc. from the net torque obtained by combustion. The present inventor has made clear by the examination. Based on the result of this examination, as shown in FIG. 8, including up to the torque calculation means 4 of the present invention shown in FIG. 2, the torque corresponding to the torque generated by the engine is used to determine the friction torque and the accessory drive torque. The torque detection device for an internal combustion engine of the first other embodiment is devised, which is provided with a torque correction means for correcting the engine output torque except the above.

The correction relational expression of the torque correction means included in the apparatus of the first embodiment mode must be determined as an empirical expression for each internal combustion engine developed by its nature, and FIG. 9 is the experimental system shown in FIG. 2 is an example of the relationship between the average value T _D of the engine output torque read by the dynamometer and the average value Tc of the engine generated torque detected by the device of the present invention shown in FIG. The relational expression of the torque correction means 5 shown in FIG. 9 to FIG. 8 is obtained as follows.

_{T D = 0.82Tc-1.1 (Kgm} ) first embodiment according to the detected engine with the apparatus of the present invention having a torque correction means 5 for correcting the torque performs a computation based on such relationship The output torque and the torque measured by the fifth journal are compared and shown in the lower and upper parts of FIG. 10, respectively. When both are overwritten on a single sheet, the two almost coincide with each other. As a result of adding various studies and ideas as described above, a device of the first embodiment for detecting a rapid fluctuation of the engine output torque corresponding to combustion of each cylinder as described above has been devised.

Furthermore, a second embodiment will be described. When the rotational speed of the engine rises, the inertia torque due to the reciprocating motion part such as the piston and connecting rod is superimposed on the engine output torque.
This torque is calculated by the formula (2) Fi = m _rec rω ² ( _COS ωt
+ R / _COS 2ωt) As shown by (2), there is a fluctuation component but no DC component. Therefore, the purpose or effect of detecting the inertia torque as the engine output torque is not to remove the engine power performance but to remove the damage caused by the torsional vibration of the surge drive system of the vehicle.

First, the configuration of the torque detection device for an internal combustion engine of the second embodiment is described.
It is shown in FIG. This structure is obtained by adding an inertia torque calculating means 9 between the crank angle detecting means 3 and the torque calculating means 4 in the structure of the present invention shown in FIG. 2 or FIG. Crank angle detecting means 3
The crank angular velocity is calculated from the output of, and the piston acceleration determined by the crank angular velocity, crank radius, and connecting rod length,
And the inertia torque is calculated from the mass of the reciprocating part. Then, the calculation output is sent via the torque calculation means 4 to the torque correction means 5 for obtaining the net torque generated by the engine.

The present inventor confirmed the engine output torque detected by the apparatus according to the second embodiment as described above by the experimental method shown in FIG. FIG. 14 (a) shows the torque T _g considering only the acupressure, and FIG. 14 (b) shows the curve of the torque T _g when the acupressure and the inertial force are taken into consideration, together with the fifth journal torque.

As is apparent from the above, the device of the second embodiment effectively compensates the inertia torque, and therefore can detect the engine output torque extremely accurately.

[First Embodiment] A first embodiment of the present invention will be described below with reference to the drawings.
FIG. 15 shows a circuit diagram of a first preferred embodiment of a torque detecting device for an internal combustion engine according to the present invention. In the first embodiment, the pressure fluctuation in the cylinder is detected as an electric signal, the pressure of a preset crank angle is used as a reference value, and the reference value is corrected to zero level. The torque generated by the engine is obtained.

The embodiment shown in FIG. 15 shows an example in which the torque detecting device for an internal combustion engine according to the present invention is applied to a four-cylinder engine,
It comprises a pressure detection circuit 100, a pressure correction circuit 200, a crank angle detection circuit 300, and a torque calculation circuit 400.

The pressure detection circuit 100 includes piezoelectric pickups 101, 106, 111 and 116 sandwiched between a spark plug provided for each cylinder and a head portion of the engine,
The mechanical vibration applied to the pickups 101, 106, 111 and 116 electrically detects the amount of fluctuation corresponding to the cylinder internal pressure. Pickup 101 has resistance 1
Operational amplifier (hereinafter referred to as operational amplifier) 103 together with 02
Connected to the non-inverting input terminal of the operational amplifier 103, the operational amplifier 103 forms an amplifier circuit together with the resistors 104 and 105, and the detection signal of the pickup 101 is amplified and supplied to the input terminal T ₁ of the pressure correction circuit 200. Similarly, the pickups 106, 111 and 116 provided in the other cylinders have the resistance 10
7, 112 and 117 together with operational amplifiers 108, 11
3, and 118 are connected to the non-inverting input terminals of the operational amplifiers 108, 113, 118, and
An amplifier circuit is formed together with 0, 114, 115, and 119, 120, and pickups 106, 111, 116 are formed.
The detection signals of the above are amplified and supplied to the input terminals T ₂ , T ₃ and T ₄ of the pressure correction circuit 200, respectively. 16th
The figure shows the pickups 101, 106, 111 and 1
It is sectional drawing for 1 cylinder which shows the attachment state to 16 engines. The piezoelectric pickup 183 is inserted and clamped between the cylinder head 181 and the spark plug 182. The pickup 183 detects a voltage proportional to the cylinder internal pressure fluctuation, and takes it out by a lead wire 184.
The voltage signal corresponding to the in-cylinder pressure variation of each cylinder, which is the output signal of the pressure detection circuit 100, is supplied to the input terminals T ₁ , T ₂ , T ₃ and T ₄ of the pressure correction circuit 200. The pressure correction circuit 200 will be described in detail below.

A voltage signal corresponding to the cylinder pressure fluctuation of the first cylinder is supplied to the input terminal T ₁ as described later, and the input terminal T ₁
Is connected to the input terminal of the analog switch 201 that connects and disconnects the analog signal, and the resistor 207. The output terminal of the analog switch 201 is connected to the non-inverting input terminal of the operational amplifier 203 together with the capacitor 202, and the analog switch 201 and the capacitor 202 together with the operational amplifier 203 form a sample and hold circuit that performs sampling and holds a sampling value. The sampling timing of the sample / hold circuit is a period during which the control terminal of the analog switch 201 is at a high level (hereinafter simply referred to as H level), and is controlled by a signal from the output terminal T ₉ of the crank angle detection circuit 300. The sample hold circuit is a pressure detection circuit 10
A circuit for detecting a value for correcting the zero level of the signal corresponding to the cylinder internal pressure fluctuation detected by 0, that is, a reference value, and detecting the pressure signal level during the period when the control terminal of the analog switch 201 is at the H level. Holds while control pin is at low level. In the illustrated embodiment, the H level period is 180 ° ATD
It is set to C to 270 ° ATDC. Operational amplifier 2
Reference numeral 04 forms a differential amplifier circuit together with the resistors 205, 206, 207 and 208, and differentially operates the output signal of the sample hold circuit and the signal from the pressure detection circuit 100. The output voltage of the operational amplifier 204 is the torque calculation circuit 4
00 to the input terminal T ₅ . The signal obtained as described above has a signal level corresponding to the cylinder pressure fluctuation detected by the pressure detection circuit 100, which is 180 ° ATDC.
It is corrected so that the level becomes zero during the period of ˜270 ° ATDC.

Similarly, signals corresponding to cylinder internal pressure fluctuations of other cylinders are also corrected to zero level by the pressure correction circuit 200, and the corrected pressure signal of the fourth cylinder is input to the input terminal T ₆ of the torque calculation circuit 400 to the second cylinder. Pressure signal to the input terminal T ₇ ,
The pressure signal of the third cylinder is supplied to each input terminal T ₈ .

The torque calculation circuit 400 uses the pressure signal from the pressure correction circuit 200 and the signal from the crank angle detection circuit 300 to
Calculates and outputs the instantaneous torque of the engine. The torque calculation formula for the four-cylinder engine that is the illustrated embodiment is as follows.
It is shown by the equation (5). The pressure of the first cylinder corrected by the pressure correction circuit 200 is P ₁ , the pressure of the second cylinder is P ₂ , the pressure of the third cylinder is P ₃ , the pressure of the fourth cylinder is P _4, and the TDC of the first cylinder is calculated. As a reference, the instantaneous torque T is T = (P ₁ + P ₄ -P ₂ -P ₃ ) Arsinωt + (P ₁ + P ₂ + P ₃ + P ₄ ) Ar ² / 2sin2ωt (5) where A Is the cylinder bore area, r is the crank radius, is the length of the connecting rod, and ω is the crank angular velocity.

Pressure correction circuit 200 supplied to torque calculation circuit 400
The pressure signal of each cylinder from
02, 403, 404, 405 and 406, an operational amplifier 408, a resistor 409,
Are supplied to the adder circuit constituted by 410, 411, 412 and 413, and (P ₁ + P ₄ -P ₂ -P ₃ ) and (P ₁ + P ₂ + P ₃ + P ₄ ) in the equation (5) are Is calculated. The calculated pressure (P ₁
+ P ₄ -P ₂ -P ₃ ), the voltage signal corresponding to (+ P ₄ -P ₂ -P ₃ ) is supplied to one input terminal of the multiplier 414, and the operational amplifier 4 is connected to the other input terminal.
A voltage signal corresponding to (sin ωt) which is the output signal of 28 is supplied, and the calculation of (P ₁ + P ₄ -P ₂ -P ₃ ) × (sin ωt) in the first term of the equation (5) is executed. The inverting amplifier circuit formed by the operational amplifier 415 and the resistors 416 and 417 amplifies the output voltage of the multiplier 414. The amplification degree determined by the resistors 416 and 417 is the cylinder bore area A of the engine in the equation (5) and
It is the same value as the constant determined by the product of the crank radius r. On the other hand, operational amplifier 408, resistors 409 and 41
The voltage signal corresponding to the output (P ₁ + P ₂ + P ₃ + P ₄ ) of the adder circuit formed by 0, 411, 412 and the resistor 413 is supplied to the inverting input terminal of the operational amplifier 418 via the resistor 419. . The resistor 419 and the operational amplifier 418 are resistors 420
At the same time, an inverting amplifier circuit is formed to amplify the voltage signal corresponding to the pressure (P ₁ + P ₂ + P ₃ + P ₄ ). Amplification degree determined by the resistance 419 and 420, and the cylinder bore area A, the determined by the length of the crank radius r and connecting rod (5) of the constant Ar ² /
It is 2. The output voltage of the inverting amplifier circuit including the operational amplifier 418 is the output of the operational amplifier 439 (sin2ωt).
Is input to the multiplier 421 together with the voltage signal corresponding to the above, and multiplication is performed. The output terminal of the operational amplifier 415 forming the inverting amplifier circuit is connected to the inverting input terminal of the operational amplifier 442 through the resistor 443 and the output terminal of the multiplier 421 is connected through the resistor 444. The operational amplifier 442 forms an adding circuit together with the resistors 443 and 444 and the resistor 445. Therefore, the operational amplifier 415 forming the inverting amplifier circuit
(P ₁ + P ₄ -P ₂ -P ₃ ) Arsinωt corresponding to the voltage signal and the multiplier 421 output (P ₁ + P ₂ + P ₃ + P ₄ ) Ar ² /
The voltage signal corresponding to 2 · sin2ωt is added by the adding circuit, and a voltage signal corresponding to the torque generated by the engine according to the equation (5) is output. The crank angle signal is supplied to the torque calculation circuit 400 together with the corrected pressure signal of each cylinder.
It is understood that inωt) and (sin2ωt) are generated. The crank angle signal is detected by the crank angle detection circuit 300. The crank angle detection circuit 300 includes a detection disc 301 directly or indirectly fixed to a crankshaft of an engine, a magnet 302 around which a pickup coil 303 is wound, and a magnet 305 around which a pickup coil 306 is wound. including. 360 magnetic bodies 304 are fixed on the concentric circle near the circumferential side surface of the detection disk 301 at every crank angle of 1 degree. Further, another magnetic material is attached to the disk 301 at the position of the top dead center of the first cylinder having a different radius. The body 307 is fixed. Therefore, the pickup coil 306 generates a crank angle detection signal at the top dead center position of the cylinder of the first cylinder, and this detection signal is passed through the buffer 309 to the logic circuits 310, 311, 312, 313, 314, 3 and 3.
15 and 316 reset terminals. Also,
A signal for each 1-degree crank angle is generated from the pickup coil 303, passes through the buffer 308, and passes through the logic circuit 3.
It is supplied to the input terminals of 10, 311, 312, 313, 314, 315 and 316. Logic circuit 310,
311, 312, 313, 314, 315 and 316
Is composed of a counter circuit, a gate circuit and the like, and operates according to the output panel signals of the buffers 308 and 309. The logic circuit 310 outputs a signal that becomes an H level only between 180 degrees and 270 degrees after the top dead center of the first cylinder, and supplies the signal to the control terminal of the analog switch 201 of the pressure correction circuit 200 via the output terminal T _9. . Similarly, the logic circuit 313 is H between 90 degrees and 180 degrees after top dead center.
Level, a signal of L level from 108 degrees to TDC after top dead center, a logic circuit 311 has an H level signal from 90 degrees to TDC after top dead center, and a logic circuit 312 indicates Outputs H-level signals between 270 degrees and top dead center,
The pressure correction circuit 200 is supplied via the output terminals T ₁₀ , T ₁₁ and T ₁₂ . In addition, the logic circuit 314 is
A signal that becomes the H level from the top dead center of the first cylinder to 180 degrees after the top dead center is output, and the logic circuit 315 outputs the signal from the top dead center of the first cylinder to the 90 degrees after top dead center and from the 180 degrees after top dead center. The logic circuit 316 outputs a signal that becomes H level between 270 degrees after top dead center, and the logic circuit 316 outputs L between 90 degrees after top dead center and 270 degrees after top dead center.
At the level, R is between 270 degrees after top dead center and 90 degrees after top dead center.
It outputs a signal that becomes a level and outputs the signals to the buffers 308 and 30.
It is supplied to the torque calculation circuit 400 together with the output signal of 9.
FIG. 17 shows a timing chart of the output waveform of the crank angle detection circuit 300 described above.

The signal from the crank angle detection circuit 300 causes the torque calculation circuit 400 to generate a voltage signal corresponding to the above (sin ωt) and (sin 2ωt). That is, the torque calculation circuit 4
The digital-analog conversion circuit composed of the 00 up / down binary counters 422 and 423, the R-2R resistance ladder-424, and the operational amplifier 425 is an analog voltage corresponding to the crank angle with the top dead center of the first cylinder as 0 degree. Output a signal. Up-down binary counter 4
A digital signal for every 1 degree of crank angle is supplied to the input terminal of 22 from the output terminal T ₁₆ of the crank angle detection circuit 300, and the output of the counter 422 is supplied to the input terminal of the counter 423. The reset terminal of the counters 422 and 423 is supplied with the first cylinder top dead center signal from the output terminal T _13, and the up / down terminals of the counters 422 and 423 are supplied from the output terminal T ₁₄ of the crank angle detection circuit 300 to the crank angle. A signal every 180 degrees is supplied. Therefore, the up / down binary counters 422 and 423 up-count the signal for each crank angle of 1 degree from the top dead center of the first cylinder to 90 degrees after the top dead center, and the counters from the top dead center of 90 degrees to 180 degrees after the top dead center.
Down count up to. Further, an operation of counting up from 180 degrees after top dead center to 270 degrees after top dead center and down counting from 270 degrees after top dead center to top dead center is performed. Since the binary outputs of the counters 422 and 423 are connected to the R-2R resistance ladder that performs addition operation and further connected to the voltage follower circuit configured by the operational amplifier 425, the operational amplifier 425 is operated from the top dead center to the top dead center. After 90
It outputs a DC voltage on a triangular wave that linearly rises up to 90 degrees and linearly drops from 90 degrees after top dead center to 180 degrees after top dead center.

The output signal of the operational amplifier 425 is the sine wave converter 4
26 and the input terminals of the cosine wave converter 427 and are converted into a sine wave signal and a cosine wave signal, respectively. Since the signal obtained by the sine wave converter 426 has a full-wave rectified waveform having a crank angle of 180 degrees as one cycle, an operational amplifier 428, resistors 429, 430,
The signal is supplied to a polarity reversing circuit formed by 431 and the analog switch 432, and the polarity of the signal of the sine wave converter 426 is reversed in the section from 180 degrees after the top dead center to the top dead center. That is, the output of the sine wave converter 426 is
It is connected to the inverting input terminal of the operational amplifier 428 via the resistor 429, and similarly, the operational amplifier 428 is connected via the resistor 430.
It is connected to the non-inverting input terminal of. Further, the resistor 431 is connected between the inverting input terminal and the output terminal of the operational amplifier 428, the input terminal of the analog switch 432 that is turned on by the L-level signal is connected to the non-inverting input terminal, and the output of the analog switch 432. The terminal is grounded. From the output terminal T ₁₅ of the crank angle detection circuit 300 to the control terminal of the analog switch 432, the H level is from top dead center to 180 degrees after top dead center, and the L level is from 180 degrees after top dead center to top dead center. Since the signal is supplied, the analog switch 432 is in the ON-ON state from 180 degrees after the top dead center to the top dead center, and is in the OFF state from the top dead center to 108 degrees after the top dead center. Therefore, when the analog switch 432 is in the ON-ON state, the non-inverting input terminal of the operational amplifier 428 is grounded.
28 constitutes an inverting amplifier circuit together with the resistors 429 and 431, and the polarity of the output signal of the sine wave converter 426 is inverted. Conversely, the analog switch 432 is off OF
In the F state, the operational amplifier 428 serves as a non-inverting amplifier circuit, and the polarity of the signal is not inverted. In this way, a sine waveform based on the top dead center of the first cylinder can be obtained from the output of the operational amplifier 428. FIG. 18 shows a timing chart of output waveforms of the output terminal T ₁₃ , the operational amplifier 425, the sine wave converter 426 and the operational amplifier 428 of the crank angle detection circuit 300. Similarly, the output of the operational amplifier 425 is supplied to the cosine wave converter 427, and the output of the cosine wave converter is the operational amplifier 43.
A period from 90 degrees after top dead center to 270 degrees after top dead center by a signal from the output terminal T ₁₇ of the crank angle detection circuit 300, which is input to the polarity reversing circuit composed of 3, resistors 434, 435, 436 and analog switch 437. The polarity of the output signal from the cosine wave converter 437 is inverted. Therefore, the operational amplifier 433 outputs a cosine waveform based on the top dead center of the first cylinder.

The sine wave output signal of the operational amplifier 428 is the multiplier 414.
And the input terminal of the multiplier 438. The multiplier 43
The cosine waveform output of the operational amplifier 433 is supplied to the other input terminal of 8 for multiplication. That is,
Since the output of the operational amplifier 428 is (sin ωt) and the output of the operational amplifier 433 is (cos ωt), the output of the multiplier 438 is (sin ωt) · (cos ωt). Further, the output signal of the multiplier 438 is supplied to the non-inverting input terminal of the operational amplifier 439. This operational amplifier 439 has resistors 440 and 441.
Together with a non-inverting amplifier circuit, the non-inverting amplifier circuit is set to double the amplification degree in this embodiment so as to double the output signal of the multiplier 438. The voltage signal corresponding to (sinωt) · (cosωt), that is, (sin2ωt) is output. The output of operational amplifier 439 is supplied to an input terminal of the multiplier 421, the output of the operational amplifier _{418 (P 1 + P 2 +} P 3 + P 4) Ar 2/2 multiplied is executed.

As described above, according to this embodiment, each cylinder internal pressure fluctuation of the four-cylinder engine is detected as mechanical vibration from the pickup, and the preset crank angle level of the detected cylinder internal pressure fluctuation signal is set to zero. By performing the correction, the instantaneous net torque generated by the engine can be accurately calculated by a simple method together with the crank angle signal. That is, in the first embodiment, when the engine is operated under various operating speeds and load conditions, the temperature condition of the engine changes, which causes zero drift of the output of the pressure detector and changes in other reference values. Although they occur, they have the advantages that they can be corrected and the instantaneous net torque of the engine can be detected with high accuracy, and that the device is highly practical.

[Second Embodiment] FIG. 19 shows the engine output torque obtained by removing the accessory drive torque and the friction torque from the net torque generated by the engine detected by the first embodiment shown in FIG. A second preferred embodiment for determining is shown. The circuit configuration of the second embodiment will be described in detail below. 19th
Figure A illustrates the input terminal of the multiplier 513 of the torque correction circuit 500 in the second embodiment, the output signal terminal T ₁₈ of the operational amplifier 442 of the torque calculation circuit 400 in the first embodiment of Fig. 15 shown as described above Is supplied via. The other input terminal of each multiplier 513 is supplied with the output signal of the operational amplifier 512 that outputs a signal inversely proportional to the engine speed, which will be described later. Further, a signal from the output terminal T ₁₆ of the crank angle detection circuit 300 shown in FIG. 15 every 1 degree of the crank angle is supplied to the input terminal of the mono-multi circuit 501,
The mono-multi circuit 501 includes a resistor 502 and a capacitor 5
A signal having a constant pulse width determined by 03 is output. The output signal from the mono-multi circuit 501 with a constant pulse width is
Resistor 504, capacitor 505 and operational amplifier 506
Is input to the integration circuit and averaged. Therefore, the output of the operational amplifier 506 becomes a DC voltage signal proportional to the engine speed. In order to obtain the engine output torque from the net torque generated by the engine, which excludes the accessory drive torque and the friction torque, the correction shown in the following equation can be performed. That is, if the engine output torque to be obtained is T _D and the net torque is T _C , it becomes possible to use the equation T _D = AT _C −B (6).

The constants A and B are functions of the engine speed, and in this second embodiment, as shown in FIGS. 20 (a) and 20 (b), the constant A has a small value as the engine speed N increases. The bird
On the contrary, the constant B takes a large value as the engine speed N increases, so that it can be corrected in the entire speed range. Since the output of the operational amplifier 506 is a DC signal proportional to the engine speed N, the resistors 507, 508, 5
An inverting addition circuit composed of 09, 510 and 511 and an operational amplifier 512 outputs a voltage signal which linearly decreases as the engine speed increases as shown in FIG. 20 (a).
The output signal of the operational amplifier 512 is the multiplier 51 described above.
Since it is supplied to the input of No. 3, the output of the multiplier 513 becomes a signal corresponding to AT _C in the equation (6). The multiplier 513
Is supplied to the non-inverting input terminal of the operational amplifier 518 via the resistor 514. Further, the output of the operational amplifier 506 is supplied to the inverting input terminal of the operational amplifier 518 via the resistor 516. The operational amplifier 518 has resistors 514,
Together with 515, 516 and 517 form a differential amplifier. Accordingly, the output of the operational amplifier 518, the signal to comply to AT _C which is the output of the multiplier 513 mentioned above,
The output voltage of the operational amplifier 506 is the voltage signal obtained by subtracting the voltage signal that linearly increases as the engine speed increases, as shown in FIG. That is, as described above
(6) is a type voltage signal to comply to (T _D = AT _C -B) is an output of the torque correction circuit 500, accessory driving torque from the net torque engine occurs, and the engine output torque, except for the friction torque I want it. Therefore, according to the second embodiment, as shown in FIG. 20, by correcting the net torque generated by the engine based on the information that is linearly related to the engine speed, the auxiliary machine drive torque and There is an advantage that the engine, which excludes the friction torque, can obtain the engine output torque that drives the drive system.

[Third Embodiment] FIG. 21 shows a preferred third embodiment in which the drive torque is obtained by designating the crank angle from the instantaneous net torque of the engine detected by the above-described first embodiment. Has been done. In the third embodiment, the torque calculation circuit 40 in the first embodiment shown in FIG. 15 described above.
By adding the drive torque detection circuit 450 and the crank angle designating circuit 350 to 0, it is aimed to detect the drive torque within the explosion stroke of each cylinder and output it as an analog voltage signal. The circuit configuration of the third embodiment will be described in detail below. The embodiment shown in FIG. 21 is supplied with a serial output signal corresponding to the instantaneous net torque output from the four-cylinder engine obtained by the first embodiment shown in FIG. 15 and integrated at a crank angle designated in advance. It is composed of a drive torque detection circuit 450 that outputs an analog signal corresponding to the drive torque for which a value is requested, and a crank angle designation circuit 350 for designating the crank angle.

The drive torque detection circuit 450 integrates the instantaneous net torque signal for a predetermined crank angle and samples and holds the final value in order to detect the drive torque signal from the instantaneous net torque signal of the engine during the explosion stroke. It is output as an analog quantity. The operational amplifier 442 of the torque calculation circuit 400 in the embodiment shown in FIG. 15 described above.
The output signal of the drive torque detection circuit 45 shown in FIG.
It is supplied to the inverting input terminal of the operational amplifier 458 via the 0 input terminal T ₁₈ and the resistor 455. The operational amplifier 45
8 and the resistor 455 form an integrating circuit together with the capacitor 456 and the analog switch 457, and the control terminal of the analog switch 457 is connected to the output of the OR gate 454. The analog switch 457 is turned off when the output of the OR gate 454 is H level and is turned on when the output of the OR gate 454 is L level. Therefore, the output of the OR gate 454 is output from the integration circuit including the capacitor 456 and the operational amplifier 458. The integration operation is performed during the H level period. The period during which the integration operation is performed is during which the output torque of the engine acts as the drive torque, and in the third embodiment shown in FIG. 21, it is set from top dead center to 100 degrees after top dead center. The output of the operational amplifier 458 of the integrator circuit has the inverted signal polarity, so that the resistance 459,
The signal is supplied to the inverting amplifier circuit formed by 460 and the operational amplifier 461, and the polarity is inverted again to make it the same as the polarity of the input signal of the integrating circuit. The output of the operational amplifier 461 is
It is supplied to the input terminal of the analog switch 462. The analog switch 462 forms a sample hold circuit together with the capacitor 463 and the operational amplifier 464.
The sampling timing of this sample hold circuit is about 100 degrees after the top dead center before and after the integration circuit finishes the integration operation, and the sampling signal is supplied by supplying the output signal of the mono-multi circuit 451 to the control terminal of the analog switch 462. To be done. Capacitor 452 and resistor 45
The mono-multi circuit 451 in which the pulse width of the output signal is determined by 3 operates at the negative edge of the signal from the crank angle designating circuit 350, and outputs a pulse signal of H bell for a short time. The signal from the crank angle designating circuit 350 is supplied to one input terminal of the OR gate 454, and the other input terminal is supplied with a short-time H-level pulse signal output from the mono-multi circuit 451. OR gate 45
4 outputs a signal obtained by logically adding two inputs. This OR
The output of the gate 454 is supplied to the control terminal of the analog switch 457, and the output of the mono-multi circuit 451 is supplied to the control terminal of the analog switch 462. Therefore, the resistor 455, the capacitor 45
6, the integration circuit including the analog switch 457 and the operational amplifier 458 performs the integration operation from the top dead center to a period of about 100 degrees after the top dead center. Analog switch 4
The sample-hold circuit formed by 62, the capacitor 463, and the operational amplifier 464 samples the final value of the integration interval and holds it until the next sampling.

The crank angle designation circuit 350 is included in the crank angle detection circuit 300 in the first embodiment shown in FIG. 15 described above, and designates the integration region of the integration circuit by the crank angle.

In the crank angle designating circuit 350, a disc 351 similar to that of the first embodiment shown in FIG. 15 is provided on the concentric circles with different radii, and is delayed by 100 degrees from the top dead center and the top dead center position with respect to the rotation direction. Magnetic bodies 354 and 355 are attached to the side. Further, other magnetic members 356 and 357 are attached at positions axially symmetrical to the positions of the magnetic members 354 and 355. The magnetic pickup 353 having the magnet 352 wound is arranged at a position where a voltage is generated at 100 degrees after the top dead center when the magnetic bodies 356 and 357 pass through. The electromagnetic pickup 353 is connected to the input terminal of the flip-flop 363 via the buffer 361. Further, the circular plate 351 has the magnetic bodies 35 with different radii.
Another magnetic body 360 is fixed at a position approximately in the center of 5 and 356, and a signal is generated by a pickup coil 359 wound around a magnet 358. The pickup coil 359 is connected to the reset terminal of the flip-flop 363 via the buffer 362. The flip-flop 363
Operates in accordance with the truth table of the following table, generates a positive voltage in the period from the top dead center of each cylinder to 100 degrees after the top dead center, and otherwise generates a voltage of O [V] and outputs its output to the mono It is supplied to the input of the multi-circuit 451 and the input of the OR gate 454.

The above-mentioned flip-flop 363, monolithic circuit 45
FIG. 22 shows a timing chart of the output waveform of the OR gate 454 and the output waveform at the output terminal T ₁₈ of the operational amplifier 442 of the first embodiment shown in FIG.

Therefore, in the third embodiment, among the instantaneous net torque of the engine, which is the output of the operational amplifier 442 shown in FIG.
Degree area (hatched portion in FIG. 22) is obtained and output as an analog serial signal, the fuel injection amount of the engine is determined by the obtained driving torque signal for each intake stroke of each cylinder. It is possible to detect the engine output by means of the engine and perform a quick control, and there is an advantage that it can be used as a feedback signal of the engine output.

[Fourth Embodiment] In FIG. 23, an inertia torque calculation circuit 600 for calculating an inertia torque from the piston acceleration and the mass of the reciprocating part is added to the first embodiment shown in FIG. Thus, a fourth preferred embodiment for detecting and outputting the output instantaneous torque of the engine will be described.

According to the first embodiment shown in FIG. 15 described above, the pressure fluctuation in the cylinder is detected as an electric signal, correction is performed to make the pressure level of the preset crank angle zero, and the corrected pressure signal is used as a basis. Shows a means for easily detecting the instantaneous net torque of the engine. In the first embodiment, the influence of the inertial force due to the piston acceleration determined by the crank angular velocity, the crank radius, and the connecting rod length and the mass of the reciprocating motion part is not taken into consideration, so that the torque detection accuracy is improved especially in the high engine speed region. Getting worse. That is, in the case of a four-cylinder engine, if the reciprocating part mass is m, the crank angular velocity is ω, and the crank radius is r, the inertia torque Ti is
It is expressed by equation (7).

Ti = -2m rec ω ² r ² · sin2 ωt (7) Crank angular velocity ω, which is a function of engine speed, is introduced as a squared term in the equation, so a large inertial force acts at high speed, and the cylinder pressure It is necessary to consider the inertia torque in the fuel torque due to. Therefore, the inertia torque calculation circuit 600 for detecting the inertia torque is added, and the output signal of the inertia torque calculation circuit 600 is added to the above-mentioned fifteenth embodiment.
There is an advantage that a more accurate torque detection device for an internal combustion engine can be configured by adding the output signal of the embodiment shown in the figure.

The circuit configuration of the fourth embodiment shown in FIG. 23 will be described in detail below. The same reference numerals as those in FIG. 15 indicate the same parts. The pressure detection circuit 100, the pressure correction circuit 200, the crank angle detection circuit 300, and the torque calculation circuit 400 are the fifteenth
The configuration and operation are similar to those of the first embodiment shown in the figure. Crank angle detection circuit 300 and torque calculation circuit 4
The output of 00 is supplied to the inertia torque calculation circuit 600.

The output of the digital-analog conversion circuit including the up / down binary counters 601, 602, the R-2R resistance ladder 603 and the operational amplifier 604 of the inertia torque calculation circuit 600 is output through the operational amplifier 607 through the sine wave converter 605 and the cosine wave converter 606, respectively. ，
Resistors 608, 609, 610, analog switch 611
Is supplied to the first polarity inverting circuit composed of the above, and the second polarity inverting circuit composed of the operational amplifier 612, the resistors 613, 614, 615, and the analog switch 616. The outputs of the operational amplifiers 607 and 612 are
Multiplication is performed by the multiplier 617, and then the operational amplifier 6
It is supplied to a non-inverting amplifier circuit composed of 18, resistors 619 and 620. Since the configuration and operation similar to those of the first embodiment shown in FIG. 15 are performed, the non-inverting amplifier circuit including the operational amplifier 618 outputs an analog voltage signal corresponding to sin2ωt. The output of the operational amplifier 618 is supplied to one input terminal of the multiplier 626. The output terminal T ₁₆ of the crank angle detection circuit 300 is connected to the input of the frequency-voltage conversion circuit 621, and the frequency-voltage conversion circuit 621 changes the frequency of the signal for each crank angle of 1 degree into an analog voltage. It is output as a voltage signal corresponding to the crank angular velocity ω. Further, the signal corresponding to the crank angular velocity ω is supplied to the squaring circuit 622 and converted into a signal corresponding to the square of the crank angular velocity signal, that is, ω ² . The output of the squaring circuit 622 is output via the resistor 624 to the operational amplifier 6
The resistor 624, which is supplied to the inverting input terminal of 23, forms an inverting amplifier circuit together with the operational amplifier 623 and the resistor 625. Since the amplification degree of the inverting amplifier circuit, which is determined by the resistors 624 and 625, is set to −2mr ² in the equation (7), the operational amplifier 623 outputs an analog voltage signal corresponding to −2mω ² r ^2. . The operational amplifier 62
The output of 3 is supplied to the other input terminal of the multiplier 626, and is multiplied with the voltage signal corresponding to sin2ωt which is the output of the operational amplifier 618. Therefore, the multiplier 62
6 is the inertia torque of a 4-cylinder engine, -2 mω ² r ²
An analog voltage signal corresponding to sin2ωt will be output. The output of the multiplier 626 is supplied to the non-inverting input terminal of the operational amplifier 627 via the resistor 629, and the voltage signal corresponding to the combustion torque obtained from the corrected internal cylinder pressure signal which is the output of the torque calculation circuit 400 is the terminal T Similarly, it is supplied to the non-inverting input terminal of the operational amplifier 627 via ₁₈ and the resistor 628. Another resistor 630 is connected to the non-inverting input terminal of the operational amplifier 627 between the ground. Further, a resistor 631 is connected to the inverting input terminal of the operational amplifier 627.
Is connected to the ground and a resistor 632 is connected between the output terminals T ₂₁ , respectively, and together with the resistors 628, 629 and 630 form a non-inverting addition circuit. Therefore, the voltage signal corresponding to the combustion torque which is the output of the torque calculation circuit 400 and the voltage signal corresponding to the inertia torque which is the output of the multiplier 626 are added, and a serial voltage signal corresponding to the output instantaneous torque of the 4-cylinder engine is output from the operational amplifier 627. Is output.

As described above, according to the above-described fourth embodiment, the inertia torque can be taken into consideration and a simple pressure detector and a crank angle detection sensor can be attached to the engine to detect the engine instantaneous torque only by finger pressure. There is an advantage that it is possible to detect accurately over the entire rotation range of the engine from a low rotation range to a high rotation range where it is necessary to consider the effect of the inertial force of the reciprocating portion.

[Fifth Embodiment] A fifth embodiment of the present invention will be described below. In the fifth embodiment, the device is constructed by using a microprocessor.

FIG. 24 is a block diagram of the fourth embodiment. 711
Reference numerals a and 711b are pressure converters, 712 is a crank angle detector, 713a and 713b are charge amplifiers, and 714 is an F / V converter for obtaining the crank angular velocity from the crank angle. 715 is an A / D converter 716 and an input / output controller 71
7 is an A / D conversion device, 718 is a central processing unit, 719 is a RAM, 720 is a ROM, and 721 is an output device.

FIG. 25 is a configuration example of the A / D conversion device 716 shown in FIG. 24. 731a to 731b, 732, 734 are sample hold circuits, 733 is a multiplexer, 735
Is an A / D converter, and 736 is an A / D conversion control circuit. The top dead center signal D of the first cylinder is used as a trigger for the A / D conversion unit 716, and the crank angle signal C for each degree is used as a sampling signal for the A / D conversion unit 716. The A / D conversion control circuit 736 controls the cylinder internal pressures A ₁ and A ₂ and the crank angular velocity B.
Signals E ₁ , E ₂ , for simultaneously sample-holding
E ₃ , the control signal F of the multiplexer 733, the signal G for sample-holding the output of the multiplexer 733, and the output from the sample-hold circuit 734 are A /
The signal H for D conversion is output.

The ROM 720 shown in FIG. 24 is a storage device in which the program shown in the flowchart of FIG.
Reference numeral 719 is a storage device for temporarily storing an intermediate calculation result when the arithmetic processing is executed according to the program. The central processing unit 718 calculates the instantaneous torque of the entire engine from the A / D converted data according to the program shown in FIG. 26 stored in the ROM 720 and outputs it to the output device 721.

Next, the operation of the fifth embodiment will be described. Signals A ₁ and A ₂ corresponding to the cylinder pressure and a signal C every 1 degree of crank angle
The crank angular velocity B whose frequency is converted by the F / V converter 714 in FIG. 24 is input to the A / D converter 716, and the top dead center signal D of the first cylinder is shown in FIG. 25.
Is inputted to the A / D conversion control circuit 736, the signals are simultaneously sampled and held by the control signals E ₁ , E ₂ , E ₃ , F, G and H for every 1 degree of crank angle, and then A / D converted. . These A / D converted data are temporarily stored in the RAM shown in FIG.
It is stored in 719 (hereinafter, step 1 shown in FIG. 25). From the measured cylinder internal pressure P ^{* (i)} _(t) , correction is performed with a predetermined angle as a reference pressure to obtain the corrected cylinder internal pressure P ⁽ⁱ⁾ _(t) (above, FIG. 26 is illustrated. Step 2). Pressure-compensated cylinder pressure P ⁽ⁱ⁾
By multiplying _(t) by the bore cross-sectional area Area, the force F _p ⁽ⁱ⁾ _(t) acting on the piston within the cylinder pressure is obtained (above step 3 shown in FIG. 26). The piston acceleration α ⁽¹⁾ is obtained from the crank radius r connecting rod length and the crank angular velocity ω that has been A / D converted, and this is multiplied by the mass Mrec of the reciprocating portion to obtain the inertial force F _j ^{(i )} _(t) is obtained (the above is step 4 shown in FIG. 26). Cylinder pressure P
⁽ⁱ⁾ by _(t) by adding the force acting on the piston F _p ⁽ⁱ⁾ _(t) and the reciprocating motion of the inertial force F _i ⁽ⁱ⁾ _(t) seeking force, further multiplied by the crank radius r Instantaneous torque T ⁽ⁱ⁾ _{(t) for} each cylinder
Is obtained (above, step 5 shown in FIG. 26). The instantaneous torque T ⁽ⁱ⁾ _(t) for each cylinder is added for all cylinders, and the instantaneous torque T (t) generated by the entire engine is calculated and output to the output device 21 (step 6 shown in FIG. 26). .

As described above, in the fifth embodiment, the moment when the force acting on the piston due to the pressure fluctuation in the cylinder and the inertial force of the reciprocating portion are generated on the drive shaft of the piston type internal combustion engine according to the piston / crank mechanism of the engine. When detecting torque, the zero pressure drift of the pressure detector due to changes in engine temperature conditions and the change in reference value are compensated by correcting the reference pressure for pressure fluctuations in the cylinders, and the moment when the engine is generated accurately The torque can be calculated. In the fifth embodiment, since the A / D converter and the central processing unit are used, there is an advantage that the system reliability is high.

When the rotational speed of the engine becomes high, the influence of the inertial force of the reciprocating part becomes large, and the torque generated by the engine may not be evaluated only by the cylinder internal pressure. FIG. 27 shows a comparison result of the torque Tg when the inertial force of the reciprocating part is not taken into consideration and the solid line is taken into consideration.
By taking into consideration the inertial force as in the embodiment described above, the momentary torque generated on the drive shaft can be preferably evaluated.

"Sixth Embodiment" Next, a sixth embodiment will be described. Similar to the fifth embodiment, the sixth embodiment has a configuration including a microprocessor, but does not include the torque due to the inertial force of the reciprocating unit handled in the fifth embodiment. , The instantaneous torque of the engine generated only by the cylinder internal pressure is obtained. FIG. 28 is a block diagram of the sixth embodiment, in which the F / V converter 714 for obtaining the crank angular velocity from the crank angle according to the fifth embodiment is removed. The numbers in FIG. 28 are the same as the numbers in FIG. 24. The following are examples execution of the 6 ※ ^※ explaining the operation according to the flow diagram of Figure 29 shown.

When the top dead center signal D of the first cylinder is input to the A / D conversion unit 716, that is, the A / D conversion control circuit 736 shown in FIG. 25, the signals A ₁ and A ₂ corresponding to the cylinder internal pressure are crank angle 1 After being sampled and held simultaneously every time, A / D conversion is performed. These A / D converted data are temporarily stored in the RAM 719 (the above step 1 shown in FIG. 29). From the measured cylinder internal pressure P ^{* (i)} _(t) , correction is performed using the previously designated angle as the reference pressure, and the corrected cylinder internal pressure P
⁽ⁱ⁾ _(t) is obtained (above, step 2 shown in FIG. 29). Bore cross-sectional area Area of pressure-compensated cylinder pressure P ⁽ⁱ⁾ _(t)
The force F acting on the piston due to the cylinder pressure
⁽ⁱ⁾ _(t) is calculated (above, step 3 shown in FIG. 29). A component of the force F ⁽ⁱ⁾ _(t) acting on the piston due to the cylinder internal pressure that contributes to rotationally drive the drive shaft is obtained, and is further multiplied by the crank radius r to obtain the instantaneous torque T ⁽ⁱ⁾ _(t) of each cylinder. (The above is step 4 shown in FIG. 29). The instantaneous torque T ⁽ⁱ⁾ _(t) for each cylinder is added for all cylinders to obtain the instantaneous torque T (t) generated by the entire engine and output it to the output device 721 (step 5 shown in FIG. 29).

As described above, in the sixth embodiment, when the instantaneous torque acting on the drive shaft is obtained only by the cylinder internal pressure fluctuation, the instantaneous torque is obtained by correcting the cylinder internal pressure, and the configuration is simple. There is an advantage.

Seventh Embodiment Next, a seventh embodiment will be described. The seventh embodiment is also the fifth embodiment.
In the same manner as in the fifth embodiment, a microprocessor is included, and in addition to step 6 of the program shown in FIG. 26 of the fifth embodiment, in step 6 shown in FIG. The torque and the torque lost due to friction are corrected. A flow chart of the program of the seventh embodiment is shown in FIG. According to the embodiment of FIG. 7, the engine torque is corrected by correcting the torque consumed by the auxiliary machine and friction to the instantaneous torque of the engine obtained from the cylinder internal pressure corrected in step 6 and the inertial force of the reciprocating portion. It is clear that the instantaneous torque output can be determined. Since the correction of the auxiliary machine and the friction torque varies depending on the engine rotation speed depending on the engine, the correction constant can be determined using the rotation speed when the engine is determined.

FIG. 31 shows the result of correction of the auxiliary machine and friction torque according to the seventh embodiment, the broken line shows the torque before correction,
The solid line is the corrected torque, and the dotted line is the torque of the fifth journal, which is the engine output torque measured using the experimental system in FIG. 5, and the corrected torque and the engine output torque are in good agreement. .

"Effects" As described above, the device of the present invention has the above-described configuration, and therefore has an excellent effect that the instantaneous torque generated by the internal combustion engine can be detected momentarily in a short calculation time, and the reliability is high. It has many excellent effects such as high cost and simple structure.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an engine for explaining the principle of torque measurement of the present invention, FIG. 2 is a block diagram showing the configuration of the device of the present invention, and FIG. 3 is a line showing zero drift of pressure of a pressure detector. FIG. 4 is a characteristic diagram showing changes in pressure sensitivity with temperature, FIG. 5 is a block diagram showing an experimental system for confirming the constitution of the present invention, and FIG. 6 is measured by the experimental system shown in FIG. FIG. 8 is a characteristic diagram showing a comparison between the generated torque and the torque calculated and detected by the device of the present invention. FIG. 7 is a characteristic diagram showing a comparison between the measured torque and the torque detected by the conventional device. Is a block diagram showing the first embodiment of the present invention, FIG. 9 is a graph showing the relationship between the measurement result for obtaining the correction relational expression and the detected torque by the device of the present invention, and FIG. 10 is the measurement result and the present invention. Of the corrected detection according to the first embodiment of 11 is a stroke diagram of a 4-cylinder, 4-cycle engine, FIG. 12 is a block diagram showing an embodiment of the present invention, FIG. 13 is a block diagram showing a configuration of a second embodiment, FIG. 14 is a graph showing the detection results according to the second embodiment, FIG. 15 is a circuit diagram showing the first embodiment of the present invention, and FIG. 16 is a cross-sectional view showing how the piezoelectric pickup is mounted on the engine. FIG. 17 is a timing chart of output waveforms of the crank angle detection circuit, FIG. 18 is a timing chart of output waveforms of the torque calculation circuit, FIG. 19 is a circuit diagram showing the second embodiment, and FIG. 20 is torque correction. Characteristic diagram showing the relationship between constant and engine speed,
FIG. 21 is a circuit diagram showing a third embodiment, FIG. 22 is a timing chart of output waveforms of respective parts, FIG. 23 is a circuit diagram showing the fourth embodiment, and FIG. 24 is a fifth embodiment. Block diagram, FIG. 25 is a block diagram showing a main part thereof, FIG. 26 is a flow chart showing a program of ROM, FIG. 27 is a graph showing torque when inertia force of the reciprocating motion part is not taken into consideration, and 28. FIG. 2 is a block diagram showing a sixth embodiment, second
FIG. 9 is a flow chart showing the program, FIG. 30 is a flow chart showing the program of the seventh embodiment, and FIG. 31 is a graph showing the torque correction result. 1 ... Pressure detecting means, 2 ... Pressure correcting means, 3 ... Crank angle detecting means, 5 ... Torque correcting means, 6 ... Driving torque calculating means, 9 ... Inertial torque calculating means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazumi Sumi Kazumi Sumi, Aichi Prefecture, Nagakute Town, Aichi Prefecture 1 41, Yokoshiro, Nagakute, Toyota Central Research Laboratory Co., Ltd. (72) Inventor Sueharu Nagachi, Aichi County 1 in 41, Yokomichi, Yokoji Central Research Institute, Ltd. (56) Reference JP-A-53-54077 (JP, A) JP-A-56-24537 (JP, A) JP-A-59-52726 (JP) , A) JP 60-244829 (JP, A) JP 36-12698 (JP, B1) JP 3-45332 (JP, B2)

Claims (1)

[Claims] 1. In an internal combustion engine, pressure detection means for detecting pressure fluctuations in a cylinder and pressure correction means for setting a reference value of the cylinder pressure and correcting the cylinder pressure of the pressure detection means based on the reference value. And a crank angle detecting means for detecting a crank angle of the engine, a relational expression among a cylinder pressure of the pressure correcting means, a crank angular velocity from the crank angle detecting means, a piston area, a connecting rod length, and a crank arm radius. Torque calculation means for calculating the torque acting on the crankshaft in the rotational direction by adding the torque per cylinder to generate a signal corresponding to the torque of the internal combustion engine. A component that corresponds to the drive torque from the engine generated torque by designating a crank angle range of about 100 ° from the top dead center of the stroke Engine torque detecting apparatus characterized in that it comprises a driving torque calculating means for calculating.